Assembly device for resnatron filaments



J1me 1952 w. H. KOHL I 2,599,394-

ASSEMBLY DEVICE FOR RESNATRON FILAMENTS Filed NOV.' 19. 1949 5 Sheets-Sheet 1 m x m/ m? 424.4401 HKZZ.

June 1952 w. H. KOHL 2,599,394

ASSEMBLY DEVICE FOR RESNATRON FILAMENTS Filed Nov. 19, 1949 3 Sheets-Sheet 2 I/VI/E/VTOR June 3, 1952 w, KQHL 2,599,394

ASSEMBLY DEVICE FOR RESNATRON FILAMENTS Filed Nov. 19, 1949 5 Sheets-Sheet s Patented June 3, 1952 ASSEMBLY DEVICE FOR .RESNATRON 'FILAMENTS 7 Walter H. Kohl, Cedar Rapids, Iowa,-assignor to Collins Radio Company, Cedar Rapids, Iowa, a

corporation of Iowa Application'November 19, 1949,Serial No. 128,380

4 Claims.

This "invention teaches 'amethod of makin resnatron filament baskets.

During recent years there has been a general trend in the electronic art to use higher and higher frequencies. The resnatron tube has been devi e as one "device operable-at hig frequencies.

It isessentially a beam tetro'cle in which a plurality of radial beams are emanated from an annular cathode. It is necessary to maintain accurate alignment of the respective elements of thetubeand, in particular, to 'haveth'e individual emitting sections of the cathode "located accurately in angular and radial posit-ion. The resna tron cathode is called a filament basket. The basket comprisesaplurality of staple-'shapedfila mentssupported at'both ends byrings. -A voltage is applied across the rings during tube operation and the resultant current flow through the filaments -heats them until thermionic emission of electrons occurs. To obtain symmetry of operation not-only must great accuracy be maintained in spacing the filaments equidistant about the periphery of the rings, but also the distance of each filament to the "major axis of the basket must be maintained substantially the same. Heretofore the filaments "have been assembled -by hand and the assembly was a difficult, tedious, and time-consuming task.

It is an object of this invention, therefore, to provide a jig which maybe used for producing resnatron filament baskets.

A further object is to provide a jig which quickly and very accurately produces resnatron filament baskets.

=Still a further object is to provide 'a he which will reduce the cost of assembling 'a resnatron filament basket.

feature -'of this invention is found in the provision for aresnatron filament Li-ig comprising 'a 'ih'ase member which receives an upwardly extending member therein. A ring of the basket is placed-over the upwardly extending member and aring'o'f 'solderis placedon the ring of the basket. The ends of the filments are next placed into receiving slots formed in the ring and a holding ring' is received in ma-ting engagement over the first ring. The other ends are likewise held in a pairof ringsand filament engaging "and spacin members are placed "against the outer "edges of the filaments. A clamping means is threadil-y received on the upwardly *extendingmember and a plura ity of wedges hold the filament-engaging membersin place. The "entire jig is heated-in a furnace to melt the solder rings for bonding -the holdin rings of "the fitament together. The jig 2 is removed from the furnace and cooled. Upon disassembly an accurately dimensioned resnatron filament basket is obtained.

Further objects, features, and advantages of this invention will become apparerit 'from'the descriptionand claims when read in the light of the drawings; in which Fig. 1 is a perspective'view of aresnatron filament basket;

Fig. 2 is a. sectional view taken along the line 2-Z in Fig. l; and,

Fi '3 is an exploded perspective view of the jig of this invention with the respective :parts o'f the filament basketinterspersed in their respective assembly positions. I

Referring to Fig. 1 an assembled-resnatron filament basket is shown and comprises a plurality of filament staples H) with their ends iaetened 'to' holding means H and 12. Each staple is spaced equidistant about the periphery of the holding means H and I2 andthedistance to'the-center or active portions 13 of the staples from the major axis M of the completed assembly is very accurately maintained in a manner which will be later explained.

Fig.2 is asec'tional view taken along line 2- 2 in Fig. 1 and shows the component parts of the resnatron basket.

The holding means 12 which clamps the "upper ends of the filaments comprises a pair of rings Hi and H which fit to ether in mating engagement. Both rings are formed with an aligned axial opening. The upper ring l-B has an extending annular portion l 8. Asmall vertical openin I9 is formed in the top 'of ring l5 at:a position ofiset :from :the larger axial opening and extends only :partially through the;ri-ng. Theil'ower rin I] is formed with an upwardly extending portion 24' which is received in mating :engagementrby the upper ring 16. Thedistance from the axis 14 to the outer surface 22 of the extending portion 11 is carefully machined to a predetermined dimension.

"The upper ring i8 has a filament engaging portion '23 which is formed with a plurality of slots adapted to receive the ends 24 of the filament staples. The slots "are spaced equidistant about the periphery of the engaging ;portion*and when the filament ends 24 are clamped between the lo'werrin'g I! an'dth'e engagingtp'orti'onfi,the staples are spaced equidistant about the holding means I 2.

An annu'larnotchifi is iormedin the lower ring l1 and "is adapted to receive a ring of solder i211.

The ends 2 of the filaments are cut and then accurately finished to a predetermined length and are held in abutting engagement with the outer surface 22. Thus, the distance between the central portion I3 of the filament and the axis I4 is maintained constant for all the staples. This accuracy of construction maintains symmetry between the active portions I3 of the filaments and the surrounding rids and anode of the resnatron.

The bottom holding means I I also comprises a pair of rings 28 and 29 which clamp the lower ends 3| of the filament staples. The lower ring 29 has a staple engaging portion 32 which is formed with a plurality of slots for receiving the ends 3| of the filaments therein. The ring 28 fits in mating engagement with ring 29 and a ring of solder 33 fits between the two in an annular groove formed in the ring 23. The bottom holding means I I is formed with an opening 34 which is in axial alignment with the opening in the upper holding means I2 but which is substantially larger in diameter than the upper opening.

A shoulder 36 is formed in the ring 29 by counter boring the lower end of the opening 34.

The ends 3| of the staples I are maintained in abutting engagement with a shoulder 31 formed on the ring 28 and the length of the bottom ends 3| and the distance of the shoulder 31 from the axis I4 are maintained at predetermined dimensions.

A horizontal opening 38 is formed in the lower ring 29 for holding the lower holding means "I I in axial alignment with the upper holding means I 2. The manner in which the opening 38 accomplishes the alignment will be explained hereafter.

It is seen from the above description that the assembly of the resnatron filament basket involves the joining together of a relatively large number of different parts which must be very accurately positioned. For example, oftentimes 24 filament staples are assembled in one basket and it is easily understood that to align such a number of staples axially and peripherally becomes quite a task.

The jig shown in Fig. 3 has been devised to facilitate the assembly of the parts of the basket which are shown interspersed among the parts of the lie.

A base member 39 of a generally cylindrical shape is formed with a tapered opening which extends from a large diameter at the top 4| to a smaller diameter at the bottom 42. An annular shoulder 43 is formed adjacent the bottom 42 for supporting a disc 44 of the upright supporting member 46. The member 46 has an upward extending portion comprising the relatively thin shoulder 45, a longed middle section 41, and a top section 48 of smaller diameter than the middle section 41. A longitudinal slot 49 is formed in the outer surfaces of the upper section 48 and the middle section 41.

The ring 29 is received over the upward extending portion 46 and the shoulder 36 is engaged by the shoulder 45. The solder ring 33 is received in the notch and the ring 28 is received in mating engagement with the ring 29. The lower end 3| of the filaments are placed in the slots 50 between the rings 28 and 29 with the ends in abutting engagement with the shoulder 31. g

The ring I1 is received over the upright member 46 and engaged by the shoulder 52., The upper ends 24 of the filament staples are arranged about the surfaces 53 and the solder ring 21 is placed in the groove 26. The upper ring l6 4 is fitted over the lower ring I! and the filament ends are received in the slots 54.

A clamping ring 56 is received over the upright member 46 and clamped against the ring |6 by a nut '51 which is threadedly received by the upright member.

The clamping ring 56 is formed with a radial opening 58 and a vertical opening 59. A key 6| fits through the opening 58 and is received in the slot 49 for preventing rotary motion of the clamping ring. A second key 62 extends through the opening 59 and into the opening I9 in the ring I6. Thus rotary motion of the ring I6 is prevented.

Four arculately-shaped filament engaging portions 63 are fitted about the active portions I3 of the filaments. Each filament engaging portion 63 is formed with equally spaced slots 64 for receiving the filaments therein. The edges of the slots are slightly tapered outwardly to allow the jig-to be disassembled. One of the filament engaging portions is formed with a horizontal opening 66 for receiving a key 61 which extends through the opening 38 in the ring 29 and into the slot 49. This key prevents rotary motion of the ring 29 and thus the upper and lower holding means may be maintained in axial alignment.

The engaging portions 63 fit within the confines of the base member 39- and wedge members 68 are received between the inner tapered wall 69 of the base member and the outer surface II of the engaging portions.

The junctions between adjacent wedge portions 68 are placed so as to be out of radial alignment with the junctions between adjacent engaging portions 63.

When the jig has been completely assembled it is placed into a heating unit and raised to a temperature suflicient to melt the solder rings 21 and 33. The jig is then removed from the heating unit and allowed to cool. The wedges 69 are next removed and then the engaging portions 63. The nut 51 is unscrewed and the clamping ring 5|] removed.

The filament basket may then be lifted from the upright member and the finished product is obtained.

It is thus seen that this invention provides a method of making a resnatron filament basket by the use of a novel jig.

Although the invention has been described with respect to preferred embodiments thereof it is not to be so limited because modifications and changes are within the full intended scope as defined by the appended claims.

I claim:

1. A jig for producing resnatron filament baskets comprising a base member formed with an axially tapered opening and a shoulder formed in said base member adjacent the end of the tapered opening, an upright member received within said base member against the shoulder, filament engaging portions received within said base member and concentric about said upright member, clamping means connected to the upper end of said upright member, aligning means connectible with the upright member and the clamping means and wedge means received between said filament engaging portions and the tapered well of said base member.

2. A jig for assembling a plurality of stapleshaped filaments and a plurality of rings into a resnatron filament basket comprising a base member formed with a tapered axially aligned opening ending in a shoulder, an upwardly extending member received within said base member and against said shoulder and the filaments and rings of the resnatron basket assembled thereon, aligning means maintaining axial alignment between the plurality of rings and said upwardly extending member, ffilament engaging means received into the opening formed in said base member adjacent the active portions of aid filaments, and holding means received within the opening formed in said base member to secure said filament engaging means.

3. A jig for assembling a resnatron filament basket comprising, a base member formed with an axial tapered opening which extends fromv a large diameter at the top to a smaller diameter at the bottom and which is formed with an annular shoulder ad aeent the bottom. an upright supporting member with a disc attached to the lower end thereof and formed with second and third shoulders, holding means engageable with the upper end of said upright member, a plurality of arcuately shaped filament-engaging portions received about said upright member between the disc and the holding means, said disc engageable with the shoulder formed in said base member, and a plurality of Wedges received within the tapered opening of the base member and against the filament engaging portions.

4. A jig for assembling a resnatron filament basket comprising, a base member formed with a tapered axial opening which extends from a large diameter at the top to a smaller diameter at the bottom and which is formed with a shoulder adjacent the bottom, an upright supporting means with a disc attached to the lower end thereof receivable against said shoulder, said upright supporting means formed with second and third shoulders, holding means threadedly received on the upper end of said upright member, a longitudinal slot formed in said upright member, filament engaging portions received within the tapered opening between the disc and said holding means, aligning means passing through an opening formed in said filament engaging portions and received in said longitudinal slot, and a plurality of wedge members received within said tapered opening and engaged with said filament engaging portions and said base member.

WALTER H. KOHL.

EEFEE-JNGES CITED The following references are of record in. the file of this patent:

UNITED STATES PATENTS Number Name Date 1,456,506 Leveridge May 29, 1923 1,541,058 Lee June 9, 1925 1,791,781 Wilson Feb. 10, 1931 2,044,818 Spase June 23, 1936 2,296,885 Vance Sept. 29, 1942 2,327,352 Hoover Aug. 24, 1943 2,433,339 Brown Dec. 30, 1947 2,445,766 Derby et a1. July 27, 1948 2,460,120 Bondley Jan. 25, 1949 FOREIGN PATENTS Number Country Date 138,352 Great Britain -l Sept. 30, 1920 

